SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '529288b7c99b47ae6dbe30f3922a757400dfc1c7367c4d8461132e775df32912' 
  AND token = 'ttkT65hArZDHaPK/pw9weZD3k6ntBiEOGv7+6BJsWyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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