SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c6554b8a45e27ba11eee24db18785722bfb99c203a794424d7ed5146ed62175' 
  AND token = 'OPHU0v4WfQeaFJJnXzk8p0AKsWM4XyZl07vIRx/Elh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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