SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1a2e3f58280bc414c6fb56d23516831476a85163d8eb4c5e6ee130845a99233' 
  AND token = 'a7e5okl+19SIkEWmWbfAgjNB3Mzui3WowkDk+MiaIlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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