SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdae0a313e0af60596de207b62f97f90945e45da9efbdc4c019474a89339de84' 
  AND token = 'MAgZxfRW8QuL9JPjYgvhKjJ+T5Yq/681Yf9gmyONJiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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