SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '48288c1123f77516165d4baf81bd24af4a5bd7f3c652d0b5282730c2492f9909' 
  AND token = '20pWUR81faAM3HIQeQmpBjthJp3TBPs5tkrs436VMJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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