SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2ff4065b20da0772b360aa2825d395b5677a5a7f2b4ab2afb6ea1373972137a' 
  AND token = 'XhkZb+XM/51q3zeoXGpVhPSlux0gmLK9egY1d9ccGFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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