SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '940b67c31e6d797977488ba3023af1f9310c029383fe892575d341d811d03b35' 
  AND token = 'gv44QnI6avxIS0lvobG/G+cpRjzeKTl3/zYCdl6g1Hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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