SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c670c873285012d52b3ad100f426b013b9900725cd8edfe49098b0e5fc5b303f' 
  AND token = 'bN0GCAb0DqC743VNU3gpC/xqkK9aMvtwOOgb+SGWXOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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