SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afd2515be6db27e225efbbcd67f8b3cce6359e3a2535e3c8dc0440a36439cea1' 
  AND token = 'eFF6vICw9dLWjIKRtWHBywDzXuU7eOgOQFCnYe9vMsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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