SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6e570dd953708428268c83acb5483c58e8e9abab5cb5ea994517871e550e44a' 
  AND token = 'agQp0ZVFpvSzrGd/hZtBysG0ztEqZQhhO97mU6H0mjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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