SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f732a28df5aca605e8632c83be2321375c0834e05107f2727b4161d37f8e7186' 
  AND token = 'HLUotWelxwgnMr4mPvsAlWyEt8a50eXorfjIpBMsjqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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