SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27436fa6859d46ab70e0c7ebea48c0a23c8212c3bf886f5f276365c3ad61e4ee' 
  AND token = 'PWL9vva0yim8CdbUGpNRVHBzY7UjRAUU2dpUSexfLoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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