SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d4c88e3cb98c7dbced871f382a222aac793e34038d43a57e2432ec956a6bc4b' 
  AND token = '85pUUals8KX3SiPfRHj/bOM2Lynzu7ShU0xsUeMukMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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