SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '345fcd0772a7efbe9171a48b571bfa95c47527e30b1c5ed355bac2ec48962058' 
  AND token = 'rCe6Iyq1ehsJkCvb0lJD2SCIOnI+Gwnus8K1mTUEz2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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