SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4988b169566f80ca728dc9216c473e48225c7bcb6034a301a4b51f8d61f9be5' 
  AND token = 'jzgyfb88utJcuJcIUTzemfnvLOwZidtMTboCmNNsE5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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