SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0520159fa87a4a10c40335937ed9c6b523ca4b8c21a7d2384fcc5cde32435da' 
  AND token = '1PGlQ1cessDBwe1uTJahqh9uKvxVjLPu3l3kWLCgU/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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