SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '651d72d0169a518211f38ff02debfcbe2549ff55c692b01e8c90632980173598' 
  AND token = 'S1vGkEQQ5J9C11FD4ebeu8+YIOTugoMAXKMv1frHmsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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