SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '802c1911b3e8229ff873ed85045e5da76d43c62eadbec03d0d879e0544afa945' 
  AND token = 'ZriooZY546+d4q0hIzUiNJi2SLQKDkWOJPZPhFnG2CQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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