SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a0ff9e80ff11526348ed3e65c13eacdf29a5b0c297819621b726784a230fc844' 
  AND token = 'tfNAYAHI8XDMqfiXyizqFQL7ClAT+6OvtLPmFv25wkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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