SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3482a4b07a89232f7ddb5207cb0753877fcb9774945dfbea7ee63234d773c44' 
  AND token = 'n63wFul8P/KL00Kvl1s4kEbXJD+E7XL6eiBLdvPoplk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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