SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5715f7d32567695b2cd6f05be346af25e9abfad5ecd972664acb1fa6cc5ba3d7' 
  AND token = 'J9HKunix3O5UPCy0IQkYjlEQJ99PaUa2ZgmWjQbO20g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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