SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f72b1db7a08dfe43a9267bbd184b8f98c2c5c1c189d6a37fe2f32c76251102f8' 
  AND token = 'khScMUXlSVCCBFSNct8VhoqRnFJJ5H8f0LVsi4i4vJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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