SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8b569413395f85502dc6fa108b39ece7dbf6bcc718bfdb79492bad06fb162a0' 
  AND token = 'vINTYmjcmzKXG/5e9CLMB5BOncCmY+02z8qXdH4f4M8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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