SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af728316aae5ba856f4b141b886ecfe9330ea365c7fa130de444ddc2ab8e1c37' 
  AND token = 'Pe5Cjl9H8Lh5bM5XXY5vzIBlgs0d4UowDagDPzQqc+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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