SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e0d82497d388153bd8abd4977c1bbe92c49fc6bb699d103d8f133743861b0d8' 
  AND token = 'L8vVzyVigEn6HX7OW34AYrxcyrTXoPpaJY0ApVfAAjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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