SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c61bcad4ee39951d56f2924c24b6ea368c2081f39d71b197032481c42163f071' 
  AND token = 'PZp7oHd/F1jk+t8zI3ooqAp6/bFSKwc5rst/ivE+4pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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