SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a8b5b30745a66fae5612c00f9d91b450c04d2956efca7502e68154c3ed435468' 
  AND token = 'Yk35FFB12bwmaGGerVCHPtANndJj95qzg2yw8F1kk58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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