SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf7a7b2fcb2499f03003383994b37405d1598657857ead1735e409313beabb07' 
  AND token = 'SLkt5qBhdcnTqga50S3zn4scBhqe7KM+GqYS/nluWTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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