SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '818c48360dc0540b2870969911d9a66fd305f05ab56de84ed246ce4df0d928f9' 
  AND token = 'k6DJsu3tNQyj6sErPnHlmYOhI5Js5NCq4BrAx18DdME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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