SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b864ef42332d3296dfb93bd3e335240b2a5abfe85a7dca08633a055b5cce221' 
  AND token = 'ru7KQeebUOI3NNUv6gcr73bR28DAQQ2DaBxSCtEh97A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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