SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9c7f4392184681cd57934f2b83f2befa4c8926a5c67c825aa17db984af648af' 
  AND token = 'I73DskhW+rFYjPYpc1NEgzvdpzOglyZMSFZnfV6TXO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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