SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '715f869d07b5a49f43eb766d4594ddaf6d441bfb3711cd9a6572b17639201394' 
  AND token = 'fM/kR/gWIxOb33jLledrHFFrvYkHciVluD8mWODZww4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}