SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '245988160e279031766e435be68c52ef8b284fe303134ca88438238ad7b7c601' 
  AND token = '3TFPheLd/+Ha0OxUqyy8Kl3Lqo6bTFbDdMz9G+MKW20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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