SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '785c1ecd63396bbb697ae759b97f2c5a722bde6c80ea30656a1c19944c7967f4' 
  AND token = 'oBAhkOiQUJEUgXi/gbGjwIK6exr3pW5tPpBV7rwcFzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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