SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39172d055396b0fc14bcf519d447bb235e1cf8c7afa515637a2f06a224b8735e' 
  AND token = '4lMk5KdaKdggeOxElqMflECkcZJUpEdIbJtZfDAkAwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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