SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8dd7c7e40efab1c6aee0161815ffc1596f364c91c1734ec307544fd56420086' 
  AND token = 'VVYvLqERdCnqqpOwjNamYoYTfV5cdXiM6KgsESDz/LU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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