SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cec790650e301d9cb6bccce6a1c6f7b5251b5ef375996cdc7807d21395623dd' 
  AND token = 'cbou2S9odyI2WRgqPzKlb55a38M/h2VWvPyZKGjXw8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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