SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d2e8b2c5816c0c4eed9dccde23c10a98773bbfa0698386ec6030def845c26f0' 
  AND token = 'zfPYYv/4Jpu9FHvYLTZMObPUqbp5UtnPuoGOD+aoMJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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