SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8de26675fe5cbe513746a54ef4f51d3871fcfb4db9b3927b6ec8bec1fc40773' 
  AND token = 'wMv0ZR5FjP+pPSLpaE+Zk1BisTSUAFzmiwOlP52LgEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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