SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3e05ef90fd446f7abfaf413c0b7774ec9d3b5568d15a849537ae98a2b568991c' 
  AND token = '6xj6V0JhnSF/HdpJr4rjxGzgoDgQJEbFHxId6ZS0big=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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