SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b208dd98f8d36b9a6a9032032aaebf20fe7f830b87ce857aa64b55fdd003f22b' 
  AND token = '4kas9hq4idBYdiXUC3yoONAA3zEBkJDXod+PMpOF370=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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