SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5f37debfc47d365145393b2d7b933b0d819458ab79b18f28be28ae674dbf9fa4' 
  AND token = 'UQ7OhCc0rADWDorGwCJVS3anmXGuWI9gsRNiPRtdmiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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