SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d3e9eb1976686b0f6f61513150dc633c16bef1f342da8fe3cbf94ef98b3425b' 
  AND token = '6VJcvvjLuoqYTzODbXf1VgHvldpOWMGsWHZsGB4NFbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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