SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af6c28192425c020b67c2347ff642e5619191b54a9e8cccdafec3a0c3c9baab8' 
  AND token = 'roqjGB97KEUGOSsrHK1WEAwygAyIpwQ0kTeZgR5Ca80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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