SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '82f2cce19cb08784f945186affe69ae564d3e9c437d87a830564d2311b5c44c6' 
  AND token = 'PVoBmgsMO/lLdldnB9myndGvRY40lL7jk6bxxFiz334=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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