SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d2e5f5c1b0f3182ab949d1fd46b8ab4fa2e0cf2d7c3f6e88a36c70891a58137' 
  AND token = 'DljXOK5GGP0vzj0LJNUMCAxSDpyu3Hvmg4zkYfEuXmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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