SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '170181e028081f04d839783f870b4820aa98eef9e3ea8f192334e6d0aece26d5' 
  AND token = '7JJcDBq5Hw4yMPebrb3lR84bgWw73G87Jpiv1cLvAqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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