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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c50df8464d69004a8ba72ff39098596b94c28483163b5649c9b7c8c29b084d9b' 
  AND token = 'DTv7Zlseo8zQxQ1MkLeMsLWCFdDOjpb4XYZ2FRjj0bw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}