SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c350d154f192a19f539ce215b53b5475de289f02b49e556dfb95f7e519344c2' 
  AND token = 'cOyKOXnk+xprSbZBvxLvVQbdu+SNGSIWEkH373VzPsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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