SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '348d7f3754a63d04928d8cb21cdbc1fcdcef5cfa19090368ad314ea0d169c48d' 
  AND token = 'kQaFIHmcLVxGMYf9Y3vDj1B4LY6Zha7kwCXV+JKw+dg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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