SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '512fac73a26321d453330b678c82d273b655e1eb4fecbee67522185aed700096' 
  AND token = 'tLpnqaRxGgDaLH15vEAqIkwkeH6gHGvtG0ypom27Lus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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