SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32c48d292163949423ff0340a85f44ff273f83290107e3bcea730d74843456a0' 
  AND token = '/WPQkZpWVmbndgveZo9ibq3Q7MIzq8NOZkAg+q5N83Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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