SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42277a93651d5734e60fd6334fa97b56de619a54104a272f228517e9062d28ae' 
  AND token = 'WBXKg3gyMwlC0F2ceVZW1gmZu+ZwHUGCNbIeQrfFybc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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