SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af40ba6b009369e2f8d32b62dd9b3e2ac1047f5de18027a0379cc55a9b54caf6' 
  AND token = 'cEJOLmz19iFIWuJ6IhP4IBJSqsgQBBREAZMWm8hwpkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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