SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3d9c3347d5fe66317707247fad4be003394e63a575ef5adc84a9f2fb1449649' 
  AND token = 'clHzBnXF5Z8BPK+q0IsPzmVcUMPpAqVfbwqOMvhds/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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