SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '642fe567478662be3f59a842b41d45f54951f99006effae7303c7e0a26febec0' 
  AND token = 'POtK9+m+IBLZa4eBwaZjSRy9aXxszRXTTgW9thiFIes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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