SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebfae83802deb29938fd62d571ac339c9ac84617b9af070a4c282a59080216d6' 
  AND token = 'cW9pRVulqVFPvOwsqxRphH8TIdQtwCu7WB13d5TsC7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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