SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '170b587119656d32be2ab017eb89c128c80756739c4f9acd21271903d3ea2edc' 
  AND token = 'ARCgrx4qDYjAaci4HEBsC/pzuOwd1JEQ8N3pq4jN6Xk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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