SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c029a60b6424772bdd02814074bc956e26adbcc768e07730fcfc7919b9a2d368' 
  AND token = 'Mw8pYk7NDZSTdwpLLyEqXUbZrmDneS7G24aWohoZ8+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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