SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68f2f08e6674ed686d5b932757cf28fc71198990099d0a93f279709b64b556c4' 
  AND token = '7+h3NsdlsCiCCKNIJ7hy0Ahu8+vcUUnz9zl5Zy5vO6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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