SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cd3a9d3d62228477b09493b7c61a2a9bddadb84071eaf360be1cbc8c091b1311' 
  AND token = 'phJ2nekVMpfjlxx7ENHwjU2cTUh2gDpCDhovU2UnD5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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