SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e0f6d907d13b3259c66e33185d15965e01d6739c371cba4f2fff5fd49966c94' 
  AND token = 'ZhLx73BJn0f7ext8FGvjdllDBKJksxNjtQVuNw+68k8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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