SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecd61c2dd7146c73574b71847eaf9e28f8995f440f5371343501c982d85b7b8f' 
  AND token = 'r+eZsREfyitnfI/7r91c4bZztZaso4m6j6MgBYOu7ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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