SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc3c51a1c0bf974590252e9892d940cd89ff836b8f945d6d7117e079d4762a87' 
  AND token = 'wL6Gh6gT4YvYmrW/FpqaQWPlKMdZ+1dtsGp3LULzqPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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