SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c19c2112f760962845f227c3c2c58d3b8592248cdc12ac73bcfb7938872a256' 
  AND token = '6+t+2voewaoLp01uup5W08QyBcd/edGW8kWQYOpcb24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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